TREVISO and ROME, Italy, May 17, 2013 (AFP) - Bradley Wiggins, the winner of last year's Tour de France, and defending Giro d'Italia champion Ryder Hesjedal have pulled out of the Giro d'Italia cycling race due to illness, their teams announced on Friday.

Hesjedal took many by surprise by winning last year's maglia rosa (pink jersey) for the overall race winner to become the first Canadian to win a major Tour. Despite coming into this year's 96th edition in top form, Hesjedal has struggled to keep pace with the front of the peloton since the stage eight time trial. On Stage 10 he struggled on the first climb of the day, and then struggled to finish the stage.

"The conditions on yesterday's rainy, cold stage combined with Hesjedal's deteriorating physical condition proved too much and the defending champion will not take today's start," the Garmin team announced.

"It's heartbreaking," said Hesjedal. "I built my entire season around the Giro and I came here feeling great, but I have been suffering since the TT. We're working on it, but we're not sure what's wrong. There's a virus that's been going around, so it could be that, or severe allergies, or going too deep on the TT combined with both—whatever it is, I'm only getting worse.

"Yesterday's stage was just too much for me, I fought to get through it and I know everyone suffered but after seeing the medical staff last night, I also know that its time for me to go home, get some tests done and get healthy again.

"I have tried my best to honor the number one bib number, the race, my team and fans and its devastating to leave this way. Going home now is heartbreaking."

Team doctor Shannon Sovndal said, "The athlete's health is our priority. We've been trying to uncover what's going on with Ryder. He came into the race in stellar form, ready to defend his title, and clearly he's been suffering since the TT. His condition is not improving so we decided it's time for him to go home, get testing done, and focus on getting healthy again."

Like Hesjedal, Bradley Wiggins has been suffering from health problems this week.

"Due to a worsening chest infection, the decision was taken for Wiggins not to start the race's 13th stage on Friday from Busseto to Cherasco," Team Sky said in a statement.

He had struggled in the race after a head cold turned into a chest infection. He dropped more than three minutes off the pace during Thursday's 12th stage, struggling on a slippery descent to finish in 13th place overall, 5:22 minutes behind the current leader, Italy's Vincenzo Nibali, of Astana. The stage was won by former world champion and ex-Sky rider Mark Cavendish.

"We monitored Bradley overnight and this morning we've withdrawn him from the Giro after consulting the team doctor," team principal Dave Brailsford was quoted as saying on teamsky.com. "Bradley will return to the UK today for treatment and to rest and we hope to have him back on the road as soon as possible," he said.

At 254 kilometers (158 miles), Friday's 13th stage is the longest of the race, from Busseto, the birthplace of composer Giuseppe Verdi, to Cherasco.

The Giro d'Italia is one of cycling's most prestigious races and Wiggins had made the Giro's maglia rosa his primary objective before the sport's biggest showpiece, the Tour de France in July.

But despite going into the race without a hitch, he found the going tougher than expected. The former track cyclist notably lost time in the early stages, falling on the seventh stage to Pescara and found himself unable to break free on descents made even more treacherous by bad weather.

Last year's Olympic time trial gold medalist was disappointed by being unable to regain time against the clock in the eighth stage in Saltara, finishing 10secs behind his former teammate, Briton Alex Dowsett. As a result, he was only able to claw back a few seconds on Nibali, who is 41sec ahead of Australia's Cadel Evans.

Wiggins's position became even more precarious on the hilly 10th stage finishing on Altopiano del Montasio, where he lagged 37secs behind his supposed lieutenant, Colombian Rigoberto Uran.

Team Sky, which has eight riders left in the Giro, will now work for Uran, who is 2min 12secs back on Nibali in third.

Any defense of Wiggins' Tour de France crown looks to be a tall order, with the 100th edition of the race packed with mountain stages that are unlikely to be suited to Wiggins's style. In a role reversal from last year, he will work for teammate and 2012 runner-up Chris Froome, who looks likely to be one of the favorites, with Spain's Alberto Contador.